The real princess, Gu Qingluan, is adopted by the emperor. When she returns to the Minister of Revenue's residence to reunite with her birth family, they treat her with disdain. After the fake heiress frames her, Gu Qingluan fights back in public and severs ties with her. She subsequently earns the title of Princess Who Guards the Nation through her achievements in controlling locust plagues. At court, she allies with the crown prince to oppose hostile forces led by Duke Zhao. Traveling south to investigate a case, she exposes corruption and ultimately defeats her enemies, reclaims her mother's estate, and consolidates her own position.